Bulk bag liner with relief valve

ABSTRACT

A bulk bag liner comprising a sidewall forming an enclosure having at least one relief valve mounted in the sidewall thereof for expelling excess gas from within the enclosure so as to prevent elevated pressure within the enclosure and reduce the chance that the liner will rupture.

CLAIM OF PRIORITY

Applicant claims priority based on provisional application Ser. No.60/747,387 filed May 16, 2006, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

This invention relates to bulk bag liners, and more particularly to bulkbag liners having relief valves for expelling excess gas from within thebulk bag liners.

BACKGROUND AND SUMMARY OF THE INVENTION

It is well known in the art to use fluid impermeable liners within bulkbags when using bulk bags to store flowable materials that couldpermeate the walls of the bulk bags. Bulk bag liners are typicallyfilled via an inlet spout at the top thereof and emptied via an outletspout at the bottom or by perforating the film of a flat-bottomed liner.

One problem encountered when using bulk bag liners is that when theliners are filled with flowable materials the flowable materials tend tosettle within the liners creating an air pocket near the top of theliners such that the liners may rupture either due to the elevatedpressure or when other bags or items are stacked thereon. Anotherproblem is that certain flowable materials, for example calcined clay,tend to produce gas that further increases the pressure within theliners and the chances of rupture, a phenomenon known as outgassing.

This invention addresses the foregoing problems. In accordance with itsnarrower aspects, the invention comprises the use of one-way reliefvalves in the sidewalls of bulk bag liners to relieve pressure generatedby filling the liners and/or by outgassing from the flowable materialscontained by the liners.

The relief valves utilized in the manufacture of the invention are knownin the art and include means for expelling excess gas from within theliners and also for preventing gas from entering the liners from theatmosphere. In one embodiment the valve comprises a flap that opens onlyupon actuation by pressure within the liner. Further, the relief valvescontain filter means for preventing particulate within the liners fromcontacting and clogging or otherwise rendering inoperable the means forexpelling gas from within the liners. In one embodiment the filter meanscomprises a mesh layer having sufficiently small pores to preventparticulate matter from passing therethrough. Further, in one embodimentof the invention the relief valves are positioned substantially near theinlet spouts of the bulk bag liners because the contents of the linerstend to settle creating gas pockets near the tops of the liners.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention may be had byreference to the following Detailed Description when taken in connectionwith the accompanying Drawings, wherein:

FIG. 1 is perspective view of a bag liner comprising one embodiment ofthe present invention;

FIG. 2 is a perspective view from inside the bag liner shown in FIG. 1of a relief valve comprising one aspect of the present invention;

FIG. 3 is a perspective view of the relief valve shown in FIG. 2 fromoutside the bag liner shown in FIG. 1; and

FIG. 3A is a perspective view of an alternate configuration of a reliefvalve from outside a bag liner.

DETAILED DESCRIPTION

Referring to the drawings, and in particular to FIG. 1, one embodimentof the invention is illustrated. The bulk bag liner 10 comprises asidewall 12 formed from a multi-layered film. The sidewall 12 has a topend 14 and a bottom end 16 and forms an enclosure therebetween.

An inlet spout 18 is positioned at the top end 14 and is connected influid communication with the enclosure to facilitate filling of the bulkbag liner 10. An outlet spout 20 is positioned at the bottom end 16 andis also in fluid communication with the enclosure to facilitate emptyingthe bulk bag liner 10. A relief valve 22 is mounted in the sidewall 12substantially near the inlet spout 20 for expelling gas that isaccumulated within the enclosure near the top end 14. Although theembodiment shown comprises only one relief valve 22, the sidewall 12 maycomprise multiple relief valves 22 positioned about the sidewall 12 asneeded for different applications and particulates to be placed withinthe bag liner 10. In addition, the liner may comprise a flat-bottomwithout a discharge spout instead of the outlet spout 20 as needed forcertain applications and particulates to be placed therein.

FIG. 2 illustrates a perspective view of the relief valve 22 from insidethe bag liner 10. The relief valve 22 comprises a housing 24, and afilter 26 for preventing particulate matter from passing through thevalve 22. FIG. 3 illustrates a perspective view of the relief valve 22from outside the bag liner 10. The relief valve may comprise a pluralityof vents 30 perforated into the housing 24 for allowing air to expelfrom the enclosure. The valve may be a multi-part valve commerciallyavailable such as those available from Keamark, Inc. FIG. 3A illustratesa filter 22 a identical in function and structure to filter 22 exceptthe filter 22 a may comprise a different configuration of vents 30 aperforated into the sidewall 12 within the perimeter of housing 24 a.

The multi-layered film comprising the sidewall 12 may comprise a fluidimpermeable material such as aluminum foil or 6-millimeter linearlow-density polyethylene (LLDPE) along with a reinforcing material suchas polyethylene terephthalate (PET) and layers of a sealing materialsuch as high-density polyethylene, low-density polyethylene, and/orlow-density polyethylene.

Although preferred embodiments of the invention have been illustrated inthe accompanying Drawings and described in the foregoing DetailedDescription, it will be understood that the invention is not limited tothe embodiments disclosed, but is capable of numerous rearrangements,modifications, and substitutions of parts and elements without departingfrom the spirit of the invention.

1. A bulk bag liner comprising: a sidewall formed from a fluidimpermeable material and having a top and a bottom end; the sidewalldefining an enclosure; an inlet spout in fluid communication with theenclosure, the inlet spout positioned at the top end thereof; at leastone relief valve mounted in the sidewall substantially near the inletspout and comprising means for expelling gas from the enclosure andmeans for preventing particulate matter from passing through the valve.2. The bulk bag liner according to claim 1 further comprising an outletspout positioned at the bottom end of the sidewall, the outlet spout influid communication with the enclosure.
 3. The bulk bag liner accordingto claim 1 wherein the means for expelling gas from the enclosurecomprises a plurality of vents perforated in a housing comprising thevalve.
 4. The bulk bag liner according to claim 1 wherein the means forexpelling gas from the enclosure comprises a plurality of ventsperforated in the film beneath and within the perimeter of the valve. 5.The bulk bag liner according to claim 1 wherein the means for preventingparticulate matter from passing through the valve comprises a filter. 6.A bulk bag liner comprising: a sidewall having a top and a bottom end,the sidewall formed from a multi-layer film comprising a fluidimpermeable layer, at least one reinforcing layer, and at least onesealing layer; the sidewall defining an enclosure; an inlet spout influid communication with the enclosure, the inlet spout positioned atthe top end thereof; at least one relief valve mounted in the sidewallsubstantially near the inlet spout and comprising means for expellinggas from the enclosure and means for preventing particulate matter frompassing through the valve.
 7. The bulk bag liner according to claim 6further comprising an outlet spout positioned at the bottom end of thesidewall, the outlet spout in fluid communication with the enclosure. 8.The bulk bag liner according to claim 6 wherein the means for expellinggas from the enclosure comprises a plurality of vents perforated in ahousing comprising the valve.
 9. The bulk bag liner according to claim 6wherein the means for expelling gas from the enclosure comprises aplurality of vents perforated in the film beneath and within theperimeter of the valve.
 10. The bulk bag liner according to claim 6wherein the means for preventing particulate matter from passing throughthe valve comprises a filter.
 11. The bulk bag liner according to claim6 wherein the fluid impermeable layer comprises aluminum foil.
 12. Thebulk bag liner according to claim 6 wherein the fluid impermeable layercomprises linear low-density polyethylene.
 13. The bulk bag lineraccording to claim 6 wherein at least of the reinforcing layerscomprises polyethylene terephthalate.
 14. The bulk bag liner accordingto claim 6 wherein at least one of the sealing layers compriseshigh-density polyethylene.
 15. The bulk bag liner according to claim 6wherein at least one of the sealing layers comprises low-densitypolyethylene.
 16. The bulk bag liner according to claim 6 wherein atleast one of the sealing layers comprises linear low-densitypolyethylene.